Conventionally, in case medical tablets are manufactured by the use of this kind of rotary compressive molding machine if raw powder material of a medical tablet is made of a medicine formulation ingredient alone, a sticking phenomenon such that the raw powder material or the medical tablet sticks into a punch or a die might occur. In order to prevent this kind of problem, a method for tableting the powder material wherein powder lubricant such as magnesium stearate or the like is mixed into the raw powder material has been generally used.
Senile medical field is recently considered to be essential. This increases a demand for tablets which are easy to melt or collapse in a mouth so that elder persons can swallow it without difficulty or for tablets which melt immediately after swallowed so as to produce the efficacy of the medicine. However, in case the medical tablets are manufactured by the above-mentioned conventional method the powder lubricant mixed into the raw powder material hinders collapsing or melting in a mouth, which makes it difficult to meet the above-mentioned demand. In addition, due to a mixture of the powder lubricant, the tablets become fragile.
In view of the situation and with an object to prevent a sticking phenomenon considered, there is no need of mixing the powder lubricant with a medicine formulation ingredient. Then it has been examined that the lubricant is sprayed so as to adhere to a part alone where a sticking phenomenon occurs such as a surface of the punches and the tablet can be made of the powder material made of a medicine formulation ingredient alone. In view of the above, it has been conceived that powder lubricant is sprayed to the upper and the lower punches and the die hole prior to compression and molding a tablet.
However, there might be a problem that the powder lubricant is scattered when sprayed or a problem of contamination such that powder lubricant is mixed with a medicine formulation ingredient or a medicine formulation ingredient is mixed into powder lubricant when the lubricant is sprayed, resulting in unevenness of the powder lubricant adhering to the upper and lower punches. In order to prevent the powder lubricant from scattering it has been conceived that the punches are surrounded at a position where the powder lubricant is sprayed. However, this arrangement requires an opening through which the powder lubricant passes for the upper punch, thereby to be unable to suppress scattering the powder lubricant effectively.
In addition, since the powder lubricant is applied to the tip of the punch and the die hole, the quantity of the power lubricant is very subtle. However, it was difficult to measure the subtle quantity of the powder lubricant to spray the powder lubricant. For example, in a case of a storing tank in which the powder lubricant can be stored and whose bottom face is formed with an elastic membrane plate member so as to take out a subtle quantity of the powder lubricant through the bottom face thereof, wherein a small-diameter hole is provided on the membrane plate member and the membrane plate member is vibrated by a pulse air vibration wave, a quantity of the powder lubricant measured in the small-diameter hole varies according to a pulse of the pulse air vibration wave and a transformation degree of the membrane plate member, which makes it difficult to measure the quantity with accuracy. As a result of this, if a quantity of the powder lubricant is measured something over, a superfluous powder lubricant that is not applied to the tip of the punch or the die hole scatters inside the rotary compressive molding machine for powder material, resulting in growing a problem of contamination.
The present claimed invention intends to solve all of the above problems.